Annual decline in arterial blood oxygen predicts development of chronic respiratory failure in COPD with mild hypoxaemia: A 6‐year follow‐up study

• Published in: Respirology (Carlton, Vic.) Vol. 24; no. 3; pp. 262 - 269
• Main Authors: Uemasu, Kiyoshi, Sato, Susumu, Muro, Shigeo, Sato, Atsuyasu, Tanabe, Naoya, Hasegawa, Koichi, Hamakawa, Yoko, Mizutani, Tatsushi, Fuseya, Yoshinori, Tanimura, Kazuya, Takahashi, Tamaki, Hirai, Toyohiro
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.03.2019; Wiley Subscription Services, Inc
• Subjects: Aged; Aged, 80 and over; arterial blood gas; Arteries; Blood Gas Analysis; Blood pressure; Chronic Disease; Chronic obstructive pulmonary disease; emphysema; Female; Follow-Up Studies; Health risk assessment; Humans; Hypoxia - etiology; Lung diseases; Male; Middle Aged; Obstructive lung disease; Oxygen - blood; Oxygen Inhalation Therapy; Partial Pressure; Predictive Value of Tests; Prospective Studies; Pulmonary Diffusing Capacity; Pulmonary Disease, Chronic Obstructive - blood; Pulmonary Disease, Chronic Obstructive - complications; Pulmonary Disease, Chronic Obstructive - physiopathology; pulmonary function test; Respiratory failure; Respiratory function; Respiratory Insufficiency - blood; Respiratory Insufficiency - etiology; ROC Curve; Survival Rate; arterial blood gas; respiratory failure; pulmonary function test; chronic obstructive pulmonary disease; emphysema
• ISSN: 1323-7799; 1440-1843
• DOI: 10.1111/resp.13402

ABSTRACT Background and objective Chronic respiratory failure (CRF) with hypoxaemia is an important pathophysiology in patients with chronic obstructive pulmonary disease (COPD), and existing mild hypoxaemia may be a sign of future CRF development. However, little is known about the trajectory of partial arterial pressure of oxygen (PaO2) decline in patients with COPD. We assessed decline in PaO2 and the impact of short‐term reductions in PaO2 to predict future decline in PaO2. Methods A total of 172 outpatients with COPD from a prospective cohort study were enrolled. Pulmonary function tests and arterial blood gas (ABG) analyses were conducted at baseline and 1 year after enrolment and changes in PaO2 (ΔPaO2) and other parameters were calculated. Survival and incidence of CRF (as assessed by prescription of long‐term home oxygen therapy) were monitored for 6 years. Results A total of 164 patients completed the observation period and 101 patients had mild hypoxaemia (PaO2 < 80 Torr) at baseline. No patients with normal PaO2 (≥80 Torr) developed CRF, and 10 patients with mild hypoxaemia developed CRF in 6 years. Baseline airflow limitation and diffusion capacity were significantly associated with development of CRF. Receiver‐operating characteristic curve analysis showed that ΔPaO2 of −3.05 Torr/year is a useful cut‐off value to predict development of CRF in 6 years (hazard ratio (HR): 12.6, 95% CI: 3.48–58.73, P < 0.0001). Conclusion Patients with COPD and mild hypoxaemia may benefit from repeat ABG after 1 year. Although PaO2 trajectories widely varied, significant annual changes in PaO2 of at least −3.0 Torr/year were predictive of CRF development. We conducted serial arterial blood gas measurements in patients with COPD. Follow‐up partial arterial pressure of oxygen (PaO2) at 1 year in patients with mild hypoxaemia is clinically helpful since change in PaO2 (ΔPaO2) of –3.05 Torr/year predicts patients at risk of developing chronic respiratory failure within 6 years. Watch the video